The present invention evolved from efforts to provide a low cost control affording automatic shut-off of a machine after a specifid delay period. Examples of such machines are cathode ray tubes, computers and photocopiers, though the invention is of course not limited to such applications.
The invention more specifically evolved from efforts to provide an add-on device for use in combination with an elastic switch, with little or no modification of the latter, to engage the switch operator and drive it to an alternate position in response to a trip signal.